Microbatterries open up new horizons

MIT researchers are now using viruses to construct microbatteries that are half the size of a human cell.

For those of us who have often pondered how nanotechnologists plan to power their minute creations there has come news that MIT researchers are now using viruses to construct microbatteries that are half the size of a human cell.

The MIT team have used proven soft lithography technology to create a pattern of tiny posts either four or eight millionths of a metre in diameter. The researchers then deposited several layers of two polymers on top of the posts that together can act as a solid electrolyte and battery separator.

Specially modified viruses have been used to preferentially self-assemble on top of the polymer layers on the posts, to create an anode. Virus genes produce protein coats that collect molecules of cobalt oxide to form ultrathin wires or the anode.

A stamp of tiny posts, each covered with layers of electrolyte and the cobalt oxide anode, is then created and when turned over enables the electrolyte and anode to be transferred to a platinum structure. The resulting electrode arrays exhibit full electrochemical functionality according to the MIT team.

By stamping them onto a variety of surfaces the microbatteries could utlimately be used to power a range of miniature devices such as labs-on-a-chip or implantable medical sensors.

The MIT engineers still have a way to go to develop a complete microbattery but they are well on the way. They only need to create a suitable cathode using the viral assembly technique and they should have a functional solution. Once that is achieved the team plans to investigate how to create a stamp for use on curved surfaces to enable the microbatteries integrate with biological organisms.

The real beauty of the technique is that it does not involve any expensive equipment and can be carried out at room temperature so problems of scaling up production should not prove too difficult providing you can see what you are working with.